Ethereum gas: transfers and contract interactions
Estimate an Ethereum execution fee from gas used, base fee and priority fee, and understand why a contract call can cost more.
Estimated fee in ETH = gas units × (base fee gwei + priority fee gwei) / 1,000,000,000A hypothetical comparison
At a base fee of 10 gwei and a priority fee of 2 gwei, 21,000 gas gives 0.000252 ETH. A hypothetical action using 100,000 gas costs 0.0012 ETH at the same prices. If ETH is $3,000 in this scenario, those estimates are $0.756 and $3.60. These are arithmetic examples; the second gas quantity is not a quoted cost for a particular token or protocol.
| Estimated gas | Gas price | Fee in ETH | At $3,000/ETH |
|---|---|---|---|
| 21,000 | 12 gwei | 0.000252 | $0.756 |
| 100,000 | 12 gwei | 0.0012 | $3.60 |
| 100,000 | 25 gwei | 0.0025 | $7.50 |
Choose a gas estimate for the actual call
A basic transfer between ordinary accounts commonly uses 21,000 gas. Sending to a contract, transferring a token, granting approval or swapping through a protocol can require more. Wallet simulation is a better input than a generic preset because the call and its state determine the work.
Gas limit and gas used differ
The gas limit is a ceiling for execution. The final charge uses actual gas consumed and the effective gas price. A wallet’s maximum possible fee can therefore be higher than the final charge. This calculator is an estimate at the entered base and priority fees; it does not reproduce every wallet’s maximum-fee calculation.
- Read the stored base-fee timestamp before loading a network snapshot. Base fees can change before inclusion.
- Enter a priority fee deliberately. A snapshot base fee does not establish the tip for your transaction.
- Failed execution can still consume gas and incur a charge.
- Layer 2 transactions can include additional data costs. This execution-only estimate is not a full L2 fee quote.
- Approval and the later swap are separate actions if your wallet submits them separately.
Compare the receipt after sending
Use the receipt’s gas used and effective gas price to calculate the actual execution fee. The dollar conversion is separate and depends on the ETH price you choose. The calculator does not connect a wallet or submit transactions, so you can save several gas-price scenarios without granting any permissions.
Does a failed transaction cost gas?
A transaction that executes and fails can still consume gas. Estimate execution against the actual call and inspect the receipt afterward. A wallet simulation that rejects an action before sending is different from an included transaction that reverts.
Check the inputs before comparing results
- Use the gas estimate for the specific transfer or contract call.
- Keep gas units separate from the gas price in gwei.
- Layer 2 transactions can include additional data fees not modeled here.
Use the related calculator to compare your own inputs. The result is an arithmetic estimate based on the assumptions above.